Variable-stroke pump.



PATENTED JULY 11, 1905.

G. W. SINCLAIR. VARIABLE STROKE PUMP. APPLICATION FILED same} 1904.

' 4 SHEETS-SHEET 1.

PATENTED JULY 11, 1905.

G. W. SINCLAIR. VARIABLE STROKE PUMP.

APPLICATION FILED SEPT.6, 1904.

4 SHEETS-SHEET 2.

Jfivem'zr Y PATENTED JULY 11, 1905.

G. W. SINCLAIR. D VARIABLE STROKE PUMP.

APPLICATION FILED SEPT.6, 1904.

4 SHEETS-SHEET 3.

Mai/masses W 0% a d No. 794,257. I PATENTED JULY 11, 1905.

G. W. SINCLAIR.

VARIABLE STROKE PUMP. APPLILUATION P ILED SEPTA, 1904.

4 sums-SHEET 4. Q

Patented July 11, 1905.

FFICE.

PATENT GEORGE WILLIAM SINCLAIR, OF LONDON, ENGLAND, ASSIGNOR OF TIVO- THIRDS TO ROBERT W. BLAOKWELL & (10., LIMITED, OF LONDON,.

ENGLAND.

VARIABLE-STROKE PUMP.

SPECIFICATION forming part of Letters Patent No. 794,297, dated July 11, 1905.

Application filed September 6, 1904:. Serial No. 223,439.

To LL whom, it may concern.-

Be it known that I, GEORGE WILLIAM SIN- CLAIR, a subject of the King of Great Britain and Ireland, residing at 59 City road, London, E. 0., England, have invented certain new and useful Improvements in Variable Stroke Pumps and the Like, of which the following is a specification,

This invention relates to improvements in variable-stroke pumps of the type in which the variation in stroke is obtained by means of two eccentrics superimposed.

The invention is applicable to pumps having one or more plungers operated from the same shaft.

The invention relates particularly to the construction of the crank-shaft and to the method adopted for altering the position of one eccentric relatively to the other of each pair of eccentrics operating the individual plungers.

The invention briefly consists in combining with a crank-shaft having eccentric portions thereon an internal shaft fitted with pinions adapted to gear with additional eccentrics mounted on the aforesaid eccentric portions in such manner that when relative rotation between the two shafts is set up by any suitable means relative displacement of the superimposed eccentrics is obtained, so as to alter the effective stroke of the plungers or the like reciprocated by such eccentrics.

The invention also consists in providing differential gearing between the two shafts to effect the desired relative rotation thereof during the running of the pump or the like, such differential gearing being preferably simply controlled by the manipulation of a clutch.

In order that the invention may be properly understood, reference will be made to the accompanying d rawings,wherein a pump is illustrated, by way of example, with three plungers and provided with means for varying the stroke according to the invention.

Figure 1 is a side elevation showing those parts of the pump to which the invention relates.

A A, Fig. 1.

' nal shaft 9, Figs. 2 and 3) is placed therein.

crank-shaft, partly in section. Figs. 4 and 5 are sectional elevations illustrating the differential gear employed to effect the relative rotation between the shafts, Fig. 6 being a diagrammatic view illustrating some of the gear-wheels therein. Fig. 7 is a detail view of part of the difierential gear.

In carrying out the invention according to one modification as applied to a pump with three plungers the crank-shaft is provided with three sets of crank webs or eccentrics, (marked a a, I) b, and c 0.) These crank-webs are circular in section transversely to the axis of the crank-shaft, and the center of each crank-web is placed eccentrically with respect to the axis of the shaft by a distance equal to one-fourth of the full stroke of each of the plungers. Between each pair of crank-webs is a crescent-shaped portion, (shown in section at d.) The crank-shaft is hollow and a second shaft (knownhereinafter as the inter- This internal shaft is out throughout its length with a keyway, and in the intervals between the crank-webs gear-pinions, such as f, are placed, each of which pinions has a projection or key which fits into the keyway aforementioned.

Upon the outer peripheries of each pair of crank-webs is placed an eccentric e. The center of each of these eccentrics is placed relatively to the center of the crank-Webs a distance equal to a quarter of the full stroke of the plunger. The inner surfaces of these eccentrics are provided with gear-teeth which mesh or gear with the teeth on the internal pinions f. It will therefore be evident that by turning the internal shaft 9 relatively to the main crank-shaft the eccentrics 6 will be caused to rotate round the crank-webs a a, b b, c 0 and the center of each eccentric e be made to coincide with the center or axis of the main crank-shaft or be removed from it by a distance equal to half the full stroke of the pumpplungers or any intermediate distance. It will also be evident that the pairs of crankwebs a a, b b, c 0 can be placed at any angle relatively to one another, but that in a threeplunger pump, where the plungers work in one plane, it is advisable to space them one a hundred and twenty degrees apart, so as to provide for as even a turning movement as possible. Each of the outer eccentrics e is provided with an eccentric-strap 71:, Figs. 1 and 2, the straps being connected in the usual m anner to the pump-plungers.

At one end of the main crank-shaft is fixed a disk m, Fig. 4, which may also be made to serve as the main gear-wheel for transmitting the power from the electric motor or other source of power operating the pump and which is known hereinafter as the worm-disk. In Fig. i this worm-disk is shown provided with a second disk, (marked in) bolted to the former and forming with the first disk an annular chamber for carrying a supply of oil; but this latter disk is not essential. Upon the internal shaft g a worm-wheel h is securely fixed. This worm-wheel engages with a worm Z, which can be carried in brackets from either of the disks m and a, but is shown in Fig. 4: with the brackets fixed. to the disk a. This worm is free to rotate and in doing so turns the wormwheel 7L, and consequently the internal shaft g, relatively to the worm-disk m and the main crank-shaft, thereby altering the position of the external eccentrics with reference to the axis of the main crank-shaft.

In order to permit of the variation in stroke of the pump-plungers being obtained while the main shaft is rotating, a second worm-wheel is fixed on the same spindle as the worm Z and rotates with it. This worm-wheel engages with a second worm, marked 19, (shown in detail in Fig. 7.) This second worm is carried in bearings which can be fixed to either of the disks m and at; but in Fig. 7 the bearings are shown as attached to the disk 12,. Upon this spindle of this worm two gearwheels are securely fixed, (marked 9" and s in Figs. 6 and 7,) and upon an extension of the internal shaft g two gear-wheels q and t are placed. These gear-wheels are free to rotate around the internal shaft g and are provided with long sleeves or bearings for apurpose to be hereinafter described. On a journal or pin carried from either the disk m or a another gear-wheel n, Fig. 6, is provided. This gear-wheel is free to rotate upon the pin or journal aformentioned and gears with both the wheels t and s. By referring to Figs. 4 to 7 it will be evident that the wheels 9 and 1 constitute a direct train from the internal shaft 9 to the spindle of the worm p and that the wheels I? u s constitute a reversing-train from the internal shaft 9 to the spindle of the worm 2.

Upon the extension or sleeve of the gearwheel 6 the half of a claw-clutch 4; is fixed, and upon the gear-wheel q is also fixed half a clawclutch 00, and collars are provided, so that the gear-wheels q and t, with their respective clutch-disks and '0, can rotate freely around the extension of the internal shaft g,-but are restrained from moving in a longitudinal direction. Upon the sleeve forming a portion of the gear-wheel (1 another sleeve 1/ is mounted. This sleeve is provided at each end with a clutch-disk, which will engage with either of the disks 2; and aforementioned. This sleeve 7 is free to move in a longitudinal direction, but is restrained from rotating by means of a key carried from some stationary part of the pump. In Fig. 4 the key is shown as engaging in a recess formed in a portion of the casing surrounding the gear-disk m. Means are provided for moving the clutch: sleeve 1 by hand longitudinally on the shaft, so that it may engage with either of the clutchdisks 1; or 00 or be retained in a position midway between the disks. It will be evident that if the sleeve y is engaged with the clutchdisk 0) this will be restrained from rotating, as also the gear-wheel t.

Supposing the main shaft to be rotating, the wheel a, which gears with the wheel t, and the wheel 8, which gears with the wheel a, will rotate upon their axes, thereby rotating the worm p, the wormwheel 0, the worm Z, and the worm-wheel it relatively to the main shaft and causing the throw of the eccentrics to be changed, and consequently the stroke of the pump in the manner already described. If, on the other hand, the sleeve'g is made to engage with the clutch-disk w, the wheel q will be prevented from rotating and thewheel 9", which gears with it and which is fixed to the spindle of the worm 29, will rotate around its axis and in the opposite direction to that when the sleeve 9 is engaged with the clutchdisk 1). Further, the relative diameters of the wheels q, t, u, a", and s can be made so that the rate of rotation of the worm 9 shall be the same in both directions, and consequently IOO the stroke of the pump can be increased or decreased at the same rate.

As an alternative arrangement the wormwheel it can be formed as part of the disk m or may be attached to it, and the worm Zmay be carried on a bracket or disk secured to the internal shaft g.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A crank-shaft, eccentric portions thereon, an internal shaft, pinions thereon, eccentrics superimposed on said eccentric portions and engaging with the pinions and differential gearing between the shafts to enable relative rotation thereof to be effected when and as desired, substantially as described.

2. The combination with a crank-shaft, eccentric portions thereon, of an internal shaft, pinions thereon, eccentrics superimposed on said eccentric portions and means for effecting the relative rotation of the shafts comprising ried on the internal shaft, and a second Worm and Worm-Wheel fitted on the first-mentioned Worm and means for controlling the clutches by hand While the shaft is rotating, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of tWo subscribing Witnesses.

GEORGE WILLIAM SINCLAIR.

Witnesses:

R. IVEsTAooTT, H. D. JAMEsoN. 

